In reception and display of character data of radio broadcasting or television broadcasting, time to obtain character data such as a broadcast station name and broadcast content is different depending on data type, reception situation, or broadcast content. This situation causes a problem. That is, when a user changes a receiving broadcast station, or when a vehicle driven by a user comes out of a tunnel and a reception condition improves, a plurality of data is intermittently displayed, which deteriorates the visibility. More specifically, as to the data being displayed at the same screen position, displayed data is updated immediately one after another, which turns out a screen flickering problem.
As a conventional solution to such a problem, there is a known navigation system, which estimates an interval of a timing to display a next intersection with an enlarged view by computing a distance and a vehicle speed. In this solution, displaying the traffic information is not permitted when the interval is less than a predetermined time (refer to Patent Document 1, for example).
Further, concerning a display item whose display duration time is set such as a first-display with its proceeding time for 6 seconds and a second-display for 3 seconds, if the second-display is prioritized to be executed after 2 seconds from the starting of the first-display execution, for instance, the first-display would be displayed only for 1 second after lapsing of the second-display, which causes the display screen to flicker. Like this, there is a known system such that when the remaining time of first-display is less than a predetermined value after lapsing the proceeding time of the second-display, the first-display would not be performed for the remaining time (refer to Patent Document 2, for example).